Internet Protocol version 4 and the more recently promulgated Internet Protocol version 6 (IPv6) are well known in the art. Pursuant to these protocols, addresses serve to identify communication sources and targets to thereby facilitate the routing and delivery of corresponding messages and bearer content. A portion of these addresses comprises a so-called prefix.
Pursuant to CDMA2000 (a wireless communication standard based upon Code Division Multiple Access (CDMA)), mobile stations that support IPv6 obtain a global IPv6 address using a so-called router advertisement. In particular, following establishment of a Point-to-Point Protocol (PPP) link (during which a portion of an identifier for the mobile station is negotiated), a Packet Data Serving Node (PDSN) will source a router advertisement that contains IPv6 prefix information. The mobile station then combines that IPv6 prefix information with the previously negotiated identifier to thereby generate a global IPv6 address. The mobile station uses this global IPv6 address for subsequent communications with other nodes.
At present, not all IPv6 prefixes are wholly fungible as compared to one another. There are at least IPv6 global prefixes and so-called 6to4 prefixes. At present, a Packet Data Serving Node will determine whether to assign a global prefix or a 6to4 prefix in a given instance based on a preconfigured policy. For example, the Packet Data Serving Node may be configured to select a particular prefix type based on a domain name presented by the mobile station during Point-to-Point Protocol negotiations.
Such local policy approaches, however, do not adequately address all likely scenarios. Typically, only the mobile station knows the destination address it wishes to ultimately seek. When the target destination address comprises a global IPv6 address, then the target is reachable through an IPv6 network and therefore a global IPv6 address (and hence a global IPv6 prefix) can be successfully used as a source address by the mobile station. When the destination address comprises a 6to4 address, however, the target destination is typically not reachable via an IPv6 network and hence a 6to4 address (and prefix) should be used for a source address.
One proposed solution has the Packet Data Serving Node providing both a global IPv6 prefix and a 6to4 prefix, presuming that the mobile station can then select and use the most appropriate prefix commensurate with its needs. Such an approach, however, represents an obviously inefficient allocation of available prefix resources.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will also be understood that the terms and expressions used herein have the ordinary meaning as is usually accorded to such terms and expressions by those skilled in the corresponding respective areas of inquiry and study except where other specific meanings have otherwise been set forth herein.